A wide variety of bioassays involve the binding or attachment of biomolecules, such as nucleic acids or proteins, on substrates. For example, microarrays are arrays of very small sample biomolecules, such as DNA or protein target material attached or bound as small spots on a solid substrate, typically a glass slide similar to a microscope slide. The attached or bound spots in the array are exposed to complementary genetic or protein probe samples derived from entities that have been tagged with fluorescent dyes. The probe material binds selectively to target spots where complementary bonding sites occur from a process called hybridization. Dissimilar probe molecules will not bind to the target molecules and will be washed away in a subsequent rinsing process. By measuring the quantity of bound probe molecules, a researcher can determine the affinity between the probe and the target molecules. This technique is used to measure a variety of biological characteristics including gene expression, genotype and gene sequence.
After hybridization, microarrays are imaged or scanned in an apparatus that illuminates the probe biomolecules with light which excites the fluors in the probe DNA causing the fluors to fluoresce. The brightness of each specimen or spot in the microarray is a function of the fluor density in that specimen or spot. The fluor density is, in turn, a function of the binding affinity of the probe molecule to the target molecule for each spot.
The surface chemistry and the surface morphology of the microarray substrate is a factor that impacts the quality of microassay readings. The surfaces of both organic and inorganic substrates are typically modified by the deposition of a coating or a polymeric monolayer film to improve binding or attachment of biomolecules, promote adhesion and lubrication, modify the electrical and optical properties of the substrate surface, and create electroactive films suitable for various optical and electronic sensors and devices. Poor quality substrates result in low DNA binding efficiency, poor spot morphology, and fluorescent background that can be unacceptably high and nonuniform. Microarray substrates are susceptible to damage and degradation of the surface chemistry if they are not stored properly. Therefore, there is a need for a way to store microarray substrates so that they are not degraded or damaged over time.